1. Field of the Invention
The present invention relates to an auto-focusing lens driving device, and more particularly, to an auto-focusing lens driving device applicable to photographing modules.
2. Description of the Prior Art For many electronic devices with the photographing function, such as a camera-embedded mobile phone and a camera with an auto-focus module, the installation of an auto-focusing lens driving device therein is required. Among the most commonly employed auto-focusing lens driving devices is the voice coil motor (VCM). The voice coil motor is suitable for use as a short-range microactuator for electronic devices due to its inexpensive price and its capability of effecting precise movements.
FIGS. 1 and 2 are side and rear views, respectively, of a prior art auto-focusing lens driving device 11. The auto-focusing lens driving device 11 comprises a cylinder-shaped lens carrier 12 whose exterior is wounded with a coil 13 and whose interior defines a hollow portion for receiving a lens assembly 14 and two separate conductive elastic pieces 15, each of which is disposed at one side of the cylinder-shaped lens carrier 12 along an optical axis (the conductive elastic piece disposed at the front side of the auto-focusing lens driving device 11 is not shown).
FIG. 3 is a sectional view of FIG. 2 taken along the line I-I, and FIG. 4 is an enlarged view of Section A of FIG. 2. The coil 13 of the auto-focusing lens driving device 11 conducts electricity supplied from an external power source via the conductive elastic pieces 15 disposed at two sides of the cylinder-shaped lens carrier 12. Each one of the two ends of the coil 13 is joined to a corresponding one of the two conductive elastic pieces 15 by soldering technique. During the soldering process, each one of the two ends of the coil 13 must be presoldered before being soldered with solders 16 to a corresponding one of the two conductive elastic pieces 15. Problems incident to the use of prior art soldering technique are as follows: 1. as the heat radiating soldering iron is situated away from the application area, the thermal conductivity is low; 2. the use of flux during the soldering process may add to the difficulty of cleanup and reduce the yield rate of the workpiece; 3. as the viscous molten solder cannot be controlled effectively, the workpiece's quality may be adversely affected; 4. the area affected by the dissipated heat is large, causing damages to the workpiece easily. For example, dissipation of heat from the soldering iron to the conductive elastic pieces 15 may cause deterioration of the conductive elastic pieces 15. Therefore, a need exists in the art for an improved auto-focusing lens driving device which can overcome the aforementioned drawbacks in the prior art.